Some People Think Auto ISO is a Bad Choice

I'm old enough to know that no statement about the best way to make photographs is ever categorically correct. Some might say "always use a tripod" or "never use auto anything on your camera". In looking at the diverse features provided by today's modern cameras, I often wonder who uses some of them. But I'm certain that there is likely someone out there that uses each of them and has their own good reason for doing so.

Recently I witnessed a discussion amongst some very capable photographers indicating that they never use auto ISO set to ON. Personally I find auto ISO to be one of the most useful features on modern digital cameras, for increasing the speed at which I work, when I'm using my camera without a tripod. Perhaps some manufacturers have implemented this feature in a way that makes it awful, however I have not personally used any such cameras.

Method 1: Example of Me Working with Auto ISO OFF
1. I set my ISO to the lowest available ISO setting on my camera (e.g. 200)
2. I compose my image
3. Since I've chosen to work in aperture priority, I dial in f11 to get my desired depth of field, and the camera sets the shutter speed to 1/15th of a second to obtain the desired exposure.
4. I realize since I'm hand holding the camera, that I will need to make a change that allows me increase my shutter speed to at least 1/60th of a second. Here are my easiest options (yes there are others but I'll keep it simple):

• Open my aperture two stops to f5.6, allowing the camera to automatically set the shutter speed to 1/60th of a second. OR
• Increase my ISO setting two stops to allow for an exposure at 1/60th of a second using f11.

Since I chose f11 for creative reasons and the second option would only raise the ISO to 800, I'm willing to put up with some image noise to get the shot I want, so I raise the ISO to 800 (2 stops more sensitive) and
5. make the picture.

Method 2: Example of Me Working with Auto ISO ON
1. I set my camera to auto ISO ON with a Maximum sensitivity of 800 and minimum shutter speed of 1/60th of a second. This means that my camera will automatically increase my ISO if the automatically chosen shutter speed of my camera ever tries to fall below 1/60th of a second, but it won't increase it beyond ISO 800 which I've chosen as the highest acceptable ISO setting.
2. I compose my image
3. Since I've chosen to work in aperture priority, I dial in f11 to get my desired depth of field, and the camera tries to set the shutter speed to 1/15th of a second to obtain the desired exposure. Of course auto ISO doesn't allow this based on my settings and automatically chooses ISO 800 to obtain the desired exposure at 1/60th of a second at f11.
4. I then make the picture

Using auto ISO ON, when using my camera without a tripod, reduces my work flow in many situations by one step, and that speed increase is valuable to me. Have I lost control of what is going on? No I haven't. Automatic features need to be understood to use them effectively with confidence. Is method 2 better than method 1? You might think so if you also value the speed increase when using your camera without a tripod. However, if you mainly shoot using a tripod, or anything other than the lowest ISO is unacceptable to you, then method 1 may be for you. Regardless, you cannot categorically say that method 2 (using auto ISO ON) is a bad idea.